territory if the new Obama administration presses ahead with plans to build a missile defense shield in Europe.

The threat, which came just hours after the conclusion of the U.S. election, appeared intended to signal Moscow's priorities to the American president-elect. It could present an early foreign policy test for Barack Obama, who says he supports a missile defense system against Iran but has also accused the Bush administration of exaggerating the system's capabilities and rushing deployment for political purposes.

The Kremlin argues that the U.S. missile shield is a threat to Russia's national security. But the Bush administration has said it is designed only to intercept a potential nuclear launch from a country such as Iran and presents no danger to Russia, whose nuclear arsenal could easily overwhelm it.

Kremlin officials have floated plans before to move missiles into the Baltic region of Kaliningrad to counter the American shield, but Medvedev's warning was the most explicit and public statement of the threat to date by a top Russian leader. Some analysts described it as the first serious Russian military threat against the West since the fall of the Soviet Union, and it struck a discordant note amid an otherwise welcoming global reaction to Obama's election. The campaign declined to comment on Medvedev's warning.

In a wide-ranging speech in which he sharply criticized the United States but also offered to repair relations with its incoming president, Medvedev accused Washington of using Russia's recent war with Georgia as an excuse to accelerate development of the missile defense system. He said he would respond by deploying Iskander missiles "to neutralize, when necessary," the U.S. shield.

He said the missiles would be supplemented by "radioelectronic equipment" to jam the U.S. system and by naval forces, presumably missile-armed warships in the Baltic Sea. He also said he had canceled plans to dismantle three missile regiments south of Kaliningrad in the western town of Kozelsk.

"I want to stress that these are forced measures," he said. "We have told our partners more than once that we want positive cooperation, that we want to act together against common threats. But they, unfortunately, don't want to listen to us."

Iskander missiles are lightweight, high-precision, surface-to-surface rockets that can be launched quickly from mobile platforms and carry nuclear or conventional payloads. Officially, they can strike ground targets up to 170 miles away, but analysts said their actual range could be much greater.

From Kaliningrad -- a Russian exclave on the Baltic coast surrounded by Poland and Lithuania and cut off from the rest of Russia -- NATO territory would be within striking distance, including a proposed U.S. interceptor base that Poland agreed in August to host. It is unclear whether the Iskander could also hit a radar station scheduled to be built in the Czech Republic as part of the shield system.

Lithuania condemned the Russian plan and called on its NATO allies to intervene. "This is just a demonstration of force inside Russia carried out in justification of an aggressive ambition," said Defense Minister Juozas Olekas, according to the Interfax news agency.